Spring biased belt support for an accumulator conveyor



April 7, 1964 J. R. SEBASTIAN- ETAL 3,127,979

SPRING BIASED BELTSUPPORT FOR AN ACCUMULATOR CONVEYOR Filed Dec. 22, 1960 IN V EN TORS 90 JAMES A. sea/15mm NORM/W c. POEL F 3 M/IVA/AAfl J. DE e000 nuausr 1/. 2501/0/15 i A rim/wry United States Patent O 3,127,979 SPRING BIASED BELT SUPPORT FGR AN ACCUMULATOR CQNVEYOR James R. Sebastian, Norman C. Peel, Maynard J. Be Good, and August V. Redlichs, ail of Grand Rapids, Mich., assiguors to The Rapids-Standard Company, Inc, Grand Rapids, Micin, a corporation of Michigan Filed Dec. 22, 196i), Ser. No. 77,622

8 (Ilairns. (Cl. 198-160) This invention relates to support linkages, and more particularly to support linkages used with spring biased belt supports.

This invention is utilized with article conveyors which have spaced wheel track sections and an article motivating conveyor belt therebetween, and particularly with accumulator conveyors of the type disclosed in the copending application Serial No. 795,435, filed February 25, 1957, now Patent No. 3,062,059 and entitled Accumulator Conveyor.

In many instances it is necessary that accumulator conveyors be adaptable to move articles of different weights. In those conveyors which make use of parallel and spaced wheel track sections with a conveyor belt therebetween, many structures have been devised for mounting the conveyor belt so that it may be vertically adjusted. In so doing, its frictional engagement with articles traveling on the track sections may be set as necessary to induce article flow without producing excess pressure in the event it becomes necessary or desirable to stop the flow of an article or articles without stopping the belt.

Structures used in this environment have previously been disclosed. One such arrangement is shown in copending patent application Serial No. 764,919, filed October 2, 1958, now Patent No. 2,985,278 entitled Spring Biased Belt Support. Although the prior art structures provide satisfactory operation in most instances, they have been found to have certain disadvantages. One of these disadvantages is that as the belt supporting hanger swings, the movement of the bolt which attaches it to the pressure spring and restraining lever causes excess wear on the hanger and often results in inoperativeness due to galling of the hanger strap with the bolt. Another problem which has occurred is the difficulty in adjusting the exact length of the links which connect the belt supporting hanger or bracket with the trigger hanger or bracket for controlling the height of the trigger hanger. In order to adjust the height of the trigger wheels carried by the trigger hanger it was previously necessary to adjust the bolt in the anchor bracket. This is a slow and costly procedure. Furthermore, adjustment of the bolt often-times resulted in changing the tension of the spring. If this occurs the pressure necessary to actuate the unit may be eiiected sometimes.

The present invention overcomes these difficulties by separating the height adjustment from the tensioning adjustment. This is accomplished by removal of the bolt and separating the means which tensions the spring from the means which controls the height of the trigger wheels.

It is therefore an object of this invention to provide support linkages which separate the spring tensioning mechanism from the mechanism which controls the height of the trigger wheels.

Another object of this invention is to provide support linkage which is simpler in design than previously existing structures.

Still another object of this invention is to provide support linkage which is economical to manufacture and maintain.

Still another object of this invention is to provide support linkage which is readily adjustable.

These and other objects and advantages of this invention will become more apparent upon reading the following specification in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is a plan view of the support linkage of this invention shown in conjunction with a wheeled conveyor track section;

FIG. 2 is a side elevation view of the support linkage as associated with a wheeled conveyor track section;

FIG. 3 is a cross sectional view taken along the section lines III-III of FIG. 2, with the position of the conveyor belt shown.

Basically, this invention relates to support linkage which forms a part of structure used to support an article motivating conveyor belt or propelling element. This structure includes a pressure wheel assembly which is pivotally suspended from an axle carrying the wheels of a wheeled conveyor track section. The pressure wheel assembly itself supports pressure wheels which engage the conveyor belt. A tension spring is connected to the pressure wheel assembly and to a tensioning plate which is in turn pivotally suspended from another axle of the wheeled conveyor track section. The tension spring normally urges the pressure wheel assembly into engagement with the next adjacent axle which acts as a stop. The tensioning plate is provided with means whereby the tension of the spring may be increased or decreased as the situation demands. Linkage is connected between the pressure wheel assembly and a trigger wheel unit or sensing element which is pivotally suspended from a remote axle of the wheeled conveyor track section. The trigger wheel unit also has wheels which are set apart so that they come up on each side of the belt and project above the top of the belt. The height position of the trigger wheel unit is determined by the length of the linkage between the trigger wheel unit and the pressure wheel assembly. Thus, the tension of the tension spring can be varied without affecting the position of the trigger wheel unit. The linkage between the trigger wheel unit and the pressure wheel assembly is provided with an adjustment plate which controls the position of the trigger wheel unit entirely independently of the pressure wheel assembly and its tensioning means.

An additional pressure wheel assembly which for convenience is termed a support wheel assembly may be pivotally suspended from another remote axle and connected to the first mentioned pressure wheel assembly. The position of the support wheel assembly is controlled by the position of the first pressure wheel assembly by a connector member which joins them.

The support linkage assembly is designated generally as 10. The assembly includes the support wheel assembly 20, the pressure wheel assembly 35, the trigger wheel unit 60, the spring tensioning plate 50, the spring 55, the connector 75, the adjustment plate 80, and links and 90.

Referring now specifically to the details of the invention, FIG. 1 best shows a section of the wheeled conveyor track now to be described.

The wheeled conveyor track section has side rails 12 (one of which is shown) and conveyor wheel axles 13a-L positioned at spaced intervals longitudinally thereof and extending transversely therebetween. The axles 13a-L are provided with a pattern of conveyor wheels for supporting articles traveling therealong.

The support wheel assembly 20 is best shown in FIGS. 1 and 2. It has a bracket 21 which has a U-shaped saddle portion 22 which surrounds the axle 131. The bracket 21 is pivotally suspended from the axle 13L by the saddle portion 22. Retainer tabs may be struck from the saddle member 22 to retain the bracket on the axle,

or other conventional means may be utilized to secure the bracket to the axle. Arms 23 and 24 project transversely from the opposite ends of the bracket 21. A shaft 25 extends between the arms 23 and 24 and is journaled therein. The shaft 25 supports drive wheels 26 and 27 which are rotatably mounted thereon. The bottom of the bracket 21 is provided with a hook-shaped portion 28 for purposes which will be explained more fully hereinafter.

The pressure wheel assembly 35 has a bracket 36 with a U-shaped saddle portion 37 which surrounds another axle 1311. As best shown in FIGS. 1 and 2, the bracket 36 is suspended from the fourth axle removed from axle 13L from which the support wheel assembly is suspended. It has been found that spacing the pressure wheel assembly 35 from the support wheel assembly 24) this distance results in a functional structure. However, it is to be understood that within the broadest aspects of this invention the members may be spaced farther apart or closer together as the situation demands.

Bracket support arms 40 and 41 project from the bracket 36. The arms are spaced and support a shaft which extends therebetween and is journaled therein. Pressure wheels 44 and 45 are journaled on the shaft 43.

The arms 40 and 41 are extended to form stop fingers 46 and 47 on the respective members. The stop fingers 46 and 47 abut the bottom of the next adjacent axle 13G which acts as a stop member. The pivotal movement of the pressure wheel assembly 35 is limited in its pivotal movement by the axle 13G.

The bottom of the bracket 36 is split and has a pair of hook-shaped members 38 and 39 formed from the bottom edge thereof.

The trigger wheel assembly 60 is pivotally suspended from axle 13a which is the seventh removed from axle 1311. This is in a direction opposite from the position of the drive wheel assembly 249.

The trigger wheel assembly 60 has a hanger 61 with a saddle portion 62 which surrounds the axle 13a. Retainer tabs may be struck from the saddle portion and underlie the axle 13a to retain the hanger on the axle. Hanger support arms 65 and 66 project from the hanger and support a shaft 67 which is journaled thereon. The shaft 67 projects beyond the spaced support arms 65 and 66 at either end. Trigger wheels 68 and 6% are journaled on the projecting portions of the shaft 67 and assume a position outside the support arms 65 and 66 as best shown in FIG. 1. The bottom of the hanger 61 is formed in shape of a hook 63 to receive a portion of link 85 now to be described.

Link 85 is constructed from wire and is in the form of a narrow, elongated, U-shaped member. The closed end of the link 35 fits over the hook 63 of hanger 61. Retaining tabs may be struck from the hook 63 to overlie the end of link 85 and retain it in the hook. The ends of connector 85 are bent outwardly at a transverse angle to form ears 86. The ears 86 are received in an adjustment plate 80.

The adjustment plate 80 is an elongated, generally rectangular shaped member. The sides of the adjustment plate 80 have fingers 81 and 82 formed thereon throughout the length of the member. The flanges 81 and 82 are of a semi-spherical shape, as viewed in cross section. The inside diameter of the flanges 81 and 82 is slightly larger than the diameter of the wire stock from which the connector 85 is constructed.

The adjustment plate 80 is provided with a series of notches 83 positioned at graduated intervals throughout the length thereof. The notches 83 are formed in both the flanges 81 and 82 and are directly opposite each other. The notches 83 receive the ears 86 of link 85 which project through the notches and join the adjustment plate 80 to the link 85.

Another link 90, which is of the same configuration as link 85, has the ears 91 projecting through a pair of notches formed in adjustment plate 80, as best shown in FIG. 1. The closed end of the link 96 is placed over the hook 39 formed on pressure wheel assembly bracket 36. Retainer tabs may be struck from the hook 39 to retain the closed end of link 90 within the hook. Other conventional means may be utilized to retain the link 30 in place within the hook 39. Indicia may be placed adjacent the notches 83 formed in the adjustment plate 80. The position of the trigger wheel assembly 69 is determined by the length of links 35 and 90. The effective length of links and 93 is determined by the position of the ears of these members in the various notches 83.

A connector '75 joins together the drive wheel assembly 26 and the pressure wheel assembly 35. The connector '75 is made from the same stock as links 85 and 99, but is a closed member of a generally rectangular shape. One end of the connector 75 is placed in hook 28 formed on drive wheel assembly bracket 21 and the other end of the connector is placed on hook 33 formed on pressure wheel assembly bracket 36. The connector 75 may be retained in position in the respective hooks by retainer tabs struck from the hooks or by other conventional means.

A swing tension plate 56 is pivotally suspended from the axle 13 which is the second removed from axle 1311. The tension plate 56 is connected to a cradle 53 which surrounds the axle 13f. Retainer tabs are struck from the cradle 53 to retain it on the axle 13 or other conventional retaining means may be utilized. The tension plate 50 is provided with a series of apertures 51. As shown in FIGS. 1 and 3, there are nine apertures 51, five in one row and four in the other. The apertures in one row are staggered with respect to the other apertures to provide for finer adjustment. Although the tension plate 56 is shown with nine apertures, it is to be understood that within the broadest aspects of this invention the number of apertures may be increased or decreased as the situation requires.

A conventional tension spring 55 has hooks 56 and 57 formed at the opposite ends thereof. The hook 56 is passed through one of the apertures 51 in tension plate 56 and the hook 57 is fastened in a hole (not shown) in the bottom of pressure wheel assembly bracket 36. The tension spring 55 constantly urges the pressure wheels 44 and 45 into contact with a conveyor belt 15 (FIG. 3) which passes thereover, and the stop fingers 46 and 47 into engagement with the axle 136.

The conveyor belt 15 is made from conventional belting material, having a top surface with a high coefificient of friction. The belt has a rib 16 which passes between the drive wheels 26 and 27 of drive wheel assembly 20. The coaction of the rib 16 with the pressure wheels 26 and 27 provides a means for centering the belt on the conveyor track section. Additional guides (not shown) may be placed at the sides of the belt 15 to further direct the movement thereof.

Operation The support linkage of this invention operates in the environment of a wheeled conveyor track section similar to that shown in FIG. 1, with a conveyor belt 16 such as shown in FIG. 3 entrained thereover. The support wheels 26 and 27, pressure wheels 44 and 45 all engage the bottom of the conveyor belt 15. The trigger wheels are set apart so that they come up on each side of the belt and project above the top of the belt. The tension spring 55 normally urges the stop fingers 46 and 4-7 of pressure wheel assembly 35 into engagement with the axle 13G. Since the support wheel assembly 26 is connected to the pressure wheel assembly 35 by the connector 75, the support wheel assembly 26 will assume the same position as the pressure wheel assembly 35. Also, the pressure of the spring 55 applied to the pressure wheel assembly 35 will be applied to the support wheel assembly 20 via the connector 75. This pressure is increased or decreased by placing the hook 56 of spring 55 in a different aperture 51 formed in tension plate 50.

It should be noted that an increase or decrease in the tension of spring 55 merely increases or decreases the pressure applied by the stop fingers 46 and 47 to the axle 13G. This in turn regulates the reactionary forces of the drive wheels 26 and 27 and the pressure Wheels 44 and 45 to the load being carried by the conveyor belt 15. When a very light load is being carried by the conveyor the spring tension may be decreased to the point where the stop fingers 46 and 47 do not abut the axle 136. With this arrangement a very light pressure is applied to the belt by the pressure and support wheels.

Increasing or decreasing the tension of spring 55 in no way effects the height of trigger wheel 60. This is true, since the stop fingers 46 and 4-7 are normally urged into contact with the axle 13G regardless of the tension of spring 55. In the situation where the spring tension is very light the height of the trigger wheels are changed though not adversely effected. This is true, since it is desirable to lower the trigger wheels somewhat to decrease the frictional resistance which the light weight carton must overcome in passing over the trigger wheels. The height of the trigger wheel assembly 60 is then normally regulated solely by the effective length of links 85 and 90. This in turn is regulated by the position of ears 86 and 91 of the links 85 and 90 in notches 83. Since the notches 83 are graduated the links 85 and 90 are both always moved to nest adjacent slots. The distance between pairs of notches increases by of an inch. This gives a height differential of approximately A inch at the trigger wheels. Although this has been found to be a desirable increment of adjustment, it is to be understood that within the broadest scope of the invention the notches may be graduated as the situation demands.

Although this invention includes a support wheel assembly, it is to be understood that in certain installations the support wheel assembly and the connector to the pressure wheel assembly may be eliminated.

The trigger wheel assembly 60 functions to retract the pressure wheel assembly 35 and support wheel assembly 20 via the links 85, 90, and 75 when articles down stream (those that have passed over or are in contact with the trigger unit) back up on the conveyor and one is positioned such that the tirgger wheel assembly 60 is pivoted in a counterclockwise direction as viewed in FIG. 2. With the pressure wheel assembly 35 and support wheel assembly 20 retracted, the belt 15 assumes a position below the conveyor Wheels 14 and out of contact with the articles upstream (those that are approaching the trigger unit) being conveyed. The belt 15 ceases to convey the upstream articles until a proper flow is reestablished. At this time pressure of the backed up downstream article being conveyed is relieved from the trigger wheel assembly 60 and it returns to its normal position. The pressure wheel assembly 35 and drive wheel assembly again raise the belt 15 into contact with the upstream articles being conveyed under the tension of spring 55.

It can be seen that the tension of spring 55 and thus the reactionary force of the pressure wheel assembly 35 and support wheel 20 to compensate for light or heavy articles traveling on the conveyor belt 15 is separated fro-m the trigger wheel assembly 60. This provides an arrangement whereby the tension adjustment of the pressure wheel assembly 35 and support wheel assembly 20 may be accomplished in a matter of minutes. The height of the trigger wheel assembly is adjusted independently of the tension means by the adjustment plate 80. The support linkage consists of a minimum number of component parts which are simple to manufacture and maintain. If the tension spring 55 should fatigue upon extended use, it may be replaced in a matter of minutes with a new spring. This may be done without effecting in any manner the position of trigger wheel 60. Thus, the initial installation and replacement time of the support linkage of this invention is cut to a small fraction of previous arrangements. The adjustment plate also provides a means whereby the position of the trigger wheel assembly may be readily altered.

While a preferred embodiment of this invention has been described, it will be understood that modifications and improvements may be made thereto. Such of these modifications and improvements as incorporate the prin ciples of this invention are to be considered as included in the hereinafter appended claims unless these claims by their language expressly state otherwise.

We claim:

1. A device for biasing an article conveying propelling member into frictional engagement with articles received thereover and principally supported by other conveyor structure comprising; an endless driven propelling member; a pressure wheel assembly and support wheel assembly movably suspended from said other conveyor structure, connector means joining said assemblies; said assemblies having wheels engaging said article conveying propelling member; stop means; link means; resilient tensioning means connected to one of said assemblies and to said other conveyor structure, biasing said assemblies against said stop means, a trigger wheel unit movably suspended from said other conveyor structure and being connected to one of said assemblies by said link means, the position of said trigger wheel unit being determined solely by said link means irrespective of the tension of said resilient tensioning means.

2. A device for biasing an article conveying propelling member into frictional engagement with articles received thereover and principally supported by other conveyor structure as in claim 1 wherein said link means includes an adjusting plate intermediate the ends thereof to vary the position of said trigger whee-1 unit.

3. A device for biasing an article conveying propelling member into frictional engagement with articles received thereover and principally supported by other conveyor structure as in claim 1 further characterized by the provision of a tension plate means for varying the tension of said resilient tensioning means.

4. In combination with a conveyor structure including a propelling element movable between an active and a passive position with respect to a first article being conveyed along said conveyor structure in response to the presence of a second article at a predetermined point downstream of said first article, control means for moving said propelling element, comprising; a movable support determinative of the position of said propelling element, means biasing said support toward the active position of said propelling element, a sensing member movable away from a rest position by the presence of said second article at said predetermined point, a link-age connecting said sensing member and said support independently of said biasing means so as to move said support to the passive position of said propelling element when said sensing element is moved away from its rest position, and means for varying the bias of said biasing means and the length of said linkage independently of one another.

5. In combination with a conveyor structure including a propelling element movable between an active and a passive position with respect to a first article being conveyed along said conveyor structure in response to the presence of 'a second article at a predetermined point downstream of said first article, control means for moving said propelling element, comprising; a movable support determinative of the position of said propelling element, means biasing said support toward the active position of said propelling element, a sensing member movable away from a rest position by the presence of said second article at said predetermined point, a linkage connecuing said sensing member and said support independently of said biasing means so as to move said support to the passive position of said propelling element when said sensing element is moved away from its rest position,

and means for varying the bias of said biasing means and the length of said linkage independently of one another, said support comprising a bracket pivotally mounted on said conveyor structure and biased by said biasing means into engagement with a stop member.

6. A device for biasing an article conveyor propelling member into frictional engagement with articles received thereover and principally supported by other conveyor structure comprising: an endless driven article propelling member; a trigger wheel unit; said other conveyor structure having side rails and a plurality of spaced axles supporting conveyor Wheels, a pressure wheel bracket having a saddle portion pivotally depending from one of said axles, spaced arms projecting from said bracket and having pressure wheels journaled therebetween and engaging said propelling member, a spring, a tension plate pivotally supported on a second axle spaced from said one axle, said tension plate being connected to said bracket by said spring, said bracket arms having stop fingers normally urged into engagement with an adjacent axle by said spring, said brac ret having a hook portion, link means connected to said hook portion and said trigger wheel unit, said trigger wheel unit pivotally suspended from a third axle, the position of said trigger wheel unit being determined solely by the length of said link means irrespective of the tension of said spring; said bracket having another hook portion and a connector, a second bracket; said other hook portion being joined to said second bracket by said connector, said second bracket having support wheels engaging said propelling member and being pivotally mounted on a fourth axle, the position of said second bracket support wheels being determined by the position of said first mentioned bracket.

7. A device for biasing an article conveyor propelling member into frictional engagement with articles received thereover and principally supported by other conveyor structure comprising: an endless driven article propelling member; a trigger wheel unit; said other conveyor structure having side rails and a plurality of spaced axles supporting conveyor wheels, a pressure wheel bracket having a saddle portion pivotally depending from one of said axles, spaced arms projecting from said bracket and having pressure wheels journaled therebetween and engaging said propelling member, a spring, a tension plate pivotally supported on a second axle spaced from said one axle, said tension plate being connected to said bracket by said spring, said bracket arms having stop fingers normally urged into engagement with an adjacent axle by said spring, said bracket having a hook portion, link means connected to said hook portion and said trigger wheel unit, said trigger Wheel unit pivotally suspended from a third axle, the position of said trigger wheel unit being determined solely by the length of said link means irrespective of the tension of said spring; said spring having a hooked end; said tension plate having a series of apertures, the tension of said spring being increased or decreased by engaging said hooked end of said spring in a dilierent aperture of said series.

8. A device for biasing an article conveyor propelling member into frictional engagement with articles received thereover and principally supported by other conveyor structure comprising: an endless driven article propelling member; a trigger wheel unit; said other conveyor structure having side rails and a plurality of spaced axles supporting conveyor wheels, a pressure wheel bracket having a saddle portion pivotally depending from one of said axles, spaced arms projecting from said bracket and having pressure 'wheels journaled therebetween and engaging said propelling member, a spring, a tension plate lpivotaily supported on a second axle spaced from said one axle, said tension plate being connected to said bracket by said spring, said bracket arms having stop fingers normally urged into engagement with an adjacent axle by said spring, said bracket having a hook portion, link means connected to said hook portion and said trigger wheel unit, said trigger wheel unit pivotally suspended from a third axle, the position of said trigger wheel unit being determined solely by the length of said (link means irrespective of the tension of said spring; said link means including an adjustment plate and a pair of U-shaped link members, said adjustment plate having flanges formed at the side thereof, said flanges being provided with a series of oppositely disposed graduated notches, said U-shaped link members having outward-1y projecting ears, said ears fitting in said notches and the end of one of said link members being connected to said trigger wheel unit and the end of said other link member being connected to the hook portion of said bracket.

References Cited in the file of this patent UNITED STATES PATENTS 2,682,407 Huck June 29, 1954 2,729,048 Dort Jan. 3, 1956 2,736,206 Conner Feb. 28, 1956 

1. A DEVICE FOR BIASING AAN ARTICLE CONVEYING PROPELLING MEMBER INTO FRICTIONAL ENGAGEMENT WITH ARTICLES RECEIVED THEREOVER AND PRINCIPALLY SUPPORTED BY OTHER CONVEYOR STRUCTURE COMPRISING; AN ENDLESS DRIVEN PROPELLING MEMBER; A PRESSURE WHEEL ASSEMBLY AND SUPPORT WHEEL ASSEMBLY MOVABLY SUSPENDED FROM SAID OTHER CONVEYOR STRUCTURE, CONNECTOR MEANS JOINING SAID ASSEMBLIES; SAID ASSEMBLIES HAVING WHEELS ENGAGING SAID ARTICLE CONVEYING PROPELLING MEMBER; STOP MEANS; LINK MEANS; RESILIENT TENSIONING MEANS CONNECTED TO ONE OF SAID ASSEMBLIES AND TO SAID OTHER CONVEYOR STRUCTURE, BIASING SAID ASSEMBLIES AGAINST SAID STOP MEANS, A TRIGGER WHEEL UNIT MOVABLY SUSPENDED FROM SAID OTHER CONVEYOR STRUCTURE AND BEING CONNECTED TO ONE OF SAID ASSEMBLIES BY SAID LINK MEANS, THE POSITION OF SAID TRIGGER WHEEL UNIT BEING DETERMINED SOLELY BY SAID LINK MEANS IRRESPECTIVE OF THE TENSION OF SAID RESILIENT TENSIONING MEANS. 